4-168
FAST AND LS TTL DATA
MC54/74F373
FUNCTIONAL DESCRIPTION
The F373 contains eight D-type latches with 3-state output
buffers. When the Latch Enable (LE) input is HIGH, data on the
Dn inputs enters the latches. In this condition the latches are
transparent; i.e., a latch output will change state each time its
D input changes. When LE is LOW the latches store the
information that was present on the D inputs one setup time
preceding the HIGH-to-LOW transition of LE. The 3-state buffers are controlled by the Output Enable (OE
) input. When (OE)
is LOW, the buffers are in the bi-state mode. When OE
is HIGH
the buffers are in the high impedance mode, but this does not
interfere with entering new data into the latches.
D
7
O
7
D
G
O
D
6
O
6
D
G
O
D
5
O
5
D
G
O
D
4
O
4
D
G
O
D
3
O
3
D
G
O
D
2
O
2
D
G
O
D
1
O
1
D
G
O
LOGIC DIAGRAM
NOTE:
This diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
LE
OE
D
0
O
0
D
G
O
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol Parameter Min Typ Max Unit Test Conditions
V
IH
Input HIGH Voltage 2.0 V Guaranteed Input HIGH Voltage
V
IL
Input LOW Voltage 0.8 V Guaranteed Input LOW Voltage
V
IK
Input Clamp Diode Voltage –1.2 V IIN = –18 mA VCC = MIN
V
OH
Output HIGH Voltage 54, 74 2.4 3.3 V IOH = – 3.0 mA VCC = 4.5 V
74 2.7 3.3 V IOH = – 3.0 mA VCC = 4.75 V
V
OL
Output LOW Voltage 0.35 0.5 V IOL = 24 mA VCC = MIN
I
OZH
Output OFF Current — HIGH 50 µA V
OUT
= 2.7 V VCC = MAX
I
OZL
Output OFF Current — LOW –50 µA V
OUT
= 0.5 V VCC = MAX
I
IH
Input HIGH Current 20 µA VIN = 2.7 V VCC = MAX
100 µA VIN = 7.0 V VCC = MAX
I
IL
Input LOW Current –0.6 mA VIN = 0.5 V VCC = MAX
I
OS
Output Short Circuit Current (Note 2) –60 –150 mA V
OUT
= 0 V VCC = MAX
I
CCZ
Power Supply Current (All Outputs OFF) 35 55 mA OE = 4.5 V
Dn, LE = GND
VCC = MAX
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable device type.
2. Not more than one output should be shorted at a time, nor for more than 1 second.